Noosrat,
Is there a long gap between your lunch and getting home from work?
If you are lowish (ie say in the 4s) then a biscuit to tide you over whilst you're getting dinner might be OK. I tend to do this if dinner is delayed a bit, I'm more likely to go for a couple of cheese straws than sweet things though. I then adjust the insulin with my meal a shade upwards to account for it (doctor doesn't like it though and she's probably right, see below)
Regular snacks as a T1 can cause problems. If you eat something with anymore than a few carbs in then you would definitely need extra insulin. It's possible to do this but then you risk stacking your insulin (ie you are adding more insulin when earlier insulin hasn't stopped working, it can be difficult to calculate the right amount) Unfortunately you may also find that eating protein snacks can still also cause a rise in glucose levels so it's not necessarily a good answer. (this seems to vary between people a bit, I certainly find protein affects my glucose levels)
I don't live in the UK and where I live snacking isn't part of the culture for anyone except children. My doctors are very insistent that 3 regular meals a day and no snacks is more likely to lead to better control. I tend to think that they are right.
It depends though on eating a reasonably sustaining meal at lunchtime. If as many people do you have a small breakfast, not much for lunch then you will be starving before your evening meal.
The advice I was given to make sure that my lunch and dinner are well balanced with enough food from all food groups.
One way of balancing a meal is to divide your plate into quarters. 1/4 of the plate is the protein ie meat/fish, 1/2 the plate veggies or salad, 1/4 plate lower GI starchy carbs , add some dairy ie a plain yoghurt or a small piece of cheese (30-40g is considered a normal portion here) and some fruit. (so you could mix in some berries with your yoghurt) Obviously the size of your plate (ie the amount) will depend on your size and needs.
If you have to eat a sandwich for lunch you can still adapt it by having some salad + the fruit and dairy on top. It's a bit more difficult if you don't eat meat or fish.
You then need to take the right amount of insulin for your meal, obviously too much and you will be hypo later (and need to eat) and too little and your blood glucose will rise.
I've read that you are trying to learn to count carbs , it really is useful (I'd say vitally important) to learn to do this so you can adjust your dose.
I don't know if you've looked at the little booklet on the DUK site or the Bournemouth online course but both could be helpful to you
link to both here:
http://www.diabetes.org.uk/Guide-to-dia ... e-Counter/